Chain bearing seal



Nov. 19, 1946;- n. E. KEECH CHAIN BEARING SEAL Filed'llarch 4, 1943 phibian (not shown).

Patented Nov. 19, 1946 CHAIN BEARING SEAL Dana E. Keech, Riverside, Calif., assignor to Food Machinery Corporation, San Jose, Calif., a corporation of Delaware Application March 4, 1943, Serial No. 477,940

This invention relates'to flexible seals, and is particularly usefulin protecting chain bearings.

It is a broad object of the invention to provide a flexible seal which will completely exclude passage of liquid or solid material inwardly or outwardly through an annular area surrounding an axis of rotation between two adjacent members.

In heavy chains, such as used in the tracklaying belts employed on tractors, military tanks and amphibians, the problem of protecting the chain bearings by keeping these lubricated and preventing abrasive material gaining access thereto, is a diflicult one as it is necessary for these chains to operate constantly in the presence of large quantities of abrasives and, not infrequently, under water.

It is another object of my invention to provide a chain bearing seal which will retain lubricant within the bearing and exclude foreign matter from said bearings over long periods of operation under difficult conditions.

It is a further object of my invention to provide such a chain bearing seal which is especially adapted for use on the chains employed in tracklaying belts as aforesaid.

The manner of accomplishing the foregoing objects, as well as further objects and advantages, will be made manifest in the following de scription taken in connection with the accompanying drawing in which:

Fig. 1 is a fragmentary side elevational view of a track-laying belt such as used on amphibians, this belt including an endless chainincorporating the preferred embodiment of my invention.

Fig. 2 is an enlarged cross sectional view taken on the line 2-2 of Fig. 1.

Fig. 3 is a cross sectional view showing a preferred form of the seal element of my invention,

. 1 Claim. (01. 286-11) side walls extending beyond said back plate and having co-axial openings 25 and 26. Driven into these openings is a bearing sleeve 21, ends 28 of this sleeve having substantially the same outside diameters and being left extending outwardly from outer faces of the walls 23. The sleeve 21 has a journal bore 35, and a lubricant groove 35 which is packed with grease when the chain is assembled. Journalling in this bore is a link pin 4|] of an adjacent link 2|. The pin 40 preferably has a head 4| with a shoulder 42 formed between this head and the shank 43 of the pin. This shank is turned down at the opposite end 44 of the pin to provide a shoulder 45. When the chain is assembled, the pin end 44 is swedged to provide a rivet head 46.

as this element appears before it is compressed when assembled with the chain.

Fig. 4 is a view similar to Fig. 3, illustrating a modified form of the seal element of my invention.

- Fig. 5 is a diagrammatic cross sectional view of another modified form of my invention.

Referring specifically to the drawing,-Fig. '1 shows a'chain III which is part of a track-laying belt H, such as is suitable for use on an am- The chain 10 is shown as traveling around a sprocket l1 and having grousers 18 secured thereto by bolts I9. This chain includes inside or bearing links 20 and outside or plate links 2|. Each bearing link 20 includes a channel-shaped body 22 having side walls 23 joined by a back plate 2 opposite ends of the Each link 2| includes side plates 54 and 55 which are formed integral with and united. by back straps 55 (see Fig. l), which are adapted to have the grousers I 8 mounted thereon. The side plates 54 and 55 overlie the sleeve ends 28 (see Fig. 2), and have concentric openings 58 and 59 into which the pin head 4!, shoulder 42 and pin end 44 snugly fit when the chain is assembled. When the swedged head 46 is formed on the pin 40 in the assembly of the chain, this binds the plate 55 between this head and the shoulder 45 on the pin and confines the sleeve 21 between the side plates 54 and 55 with the precise spacing provided on the pin 40 between the shoulders 42 and 45. This is just enough to permit free'rotation between the sleeve 21 and the link 2! as long as the bearing surfaces are lubricated.

When assembling the chain [0, sealing elements are placed over the sleeve ends 28 and compressed between opposed radial faces 66. and 61 of the plates 54 and 55 and the side walls 23. Although not essential to the invention, I also prefer to position a circular metal band 58 about each of the elements 65- when it is thus assembled with the chain It).

The elements 55 are preferably made as shown in Fig. 3, to include a unitary ring 16 made of molded rubber or a suitable substitute therefor, and are preferably made of a grease-resistant synthetic rubber. The material in this ring is preferably of a soft synthetic rubber of a durometer hardness of from 25 to 40. The term rubher" when used hereinafter without qualification..-

is to be construed broadly as covering any of the various types of resilient materials suitable for use in the rings '16. The'side surfaces 11 of the ring [6 are preferably bevelled, as shown, but

under some circumstances it may be desirable to have these lie in radial planes.

The rubber ring I6 is formed with an internal annular channel I8, which divides the ring I6 into relatively thick side walls I9 and a relatively thin annular flexing wall 80. Faces 8| of the walls I9 are preferably also'bevelled (see' Fig. 3).

Inserted into the channel I8 i a thrust bearing 85. This is preferably of the plural ring type as shown in Fig. 3, or it may comprise any other suitable type of bearing. v

The bearing 85 is shown as comprising steel insufficient amount of friction i produced between the rubber ring faces 11 and the link faces 66 and 61 to prevent slippage between these faces .when the links are flexed excessively relative to rings 88 disposed on opposite sides of a self-lubrieating, porous-bronze ring 89.

When the chain I0 is assembled with seal elements 65 disposed over the bushing ends 28, as shown in Fig. 2, the side walls I9 of the rubber ring I6 are compressed between the link faces 66 and 61- and the bearing rings 88 so as to set up a relatively high .degree of friction between the rubber ring faces II and the link faces 66 and 61. At the same time, there is a relatively small amount of friction between the bronze ring 89 and the steel rings 88 of the bearing 85. Thus when adjacent links 20 and 2| of the chain I0 are flexed relative to each other by rotational movement about the 'axis'of the pin-40, there is a high degree of resistance to slippage between the seal element faces II and the link faces 66 and 61. This results in a torsional flexing of the annular ring walls 80 which, as shown in Fig. 2, are expanded outwardly from contact .with the bearings 85 by the compression of the rubber side walls I9 each other. This design is preferable in that it will prevent the damaging of the sealing elements 65 which might otherwise take place when the chains I0 are removed and coiled upincidental to the servicing and repair of the vehicles ring thrust bearing 85 and has wall surfaces 91 of larger inside diameter than the bearing 86.

This latter feature is to prevent too much friction developing between the seal 95 and a sleeve end 28 when assembled thereon and compressed axially. The sealing element 95 operates in identically the same manner as the sealing element 65 ing 96, of course, will develop less friction than the thrust bearing 85, but would be somewhat whenthe chain is assembled. The walls 80 may 68 with a relatively light pressure, so that any rubbing between these elements does not produce any substantial wearing of either.

While I preferably employ two of the rings 88 v with one of the rings 89 in each bearing 85, this bearing mightbe made with only two rings,'one of which is steel and the other of which is bronze and obtain practical results. f 'I have found in actual use of the invention, as

illustrated in Figs. 1, 2' and 3, withthe rubber ring I6 made of neoprene with a durometer hardness of 30, as well as in other instances with a durometer hardness of 40, that a flexing of the link equipped with these elements of 30 on each side of neutral could be obtained without damage being done to the ring I6, and without causing any slippage between the ring faces 11 and the link faces 66 and. s

The seal element 66 of my invention may be designed so that the friction between the ring faces II and the link faces 66 and 61 is so great that no matter howmuch the links be flexed rela-- tive to each other there will be no slippage .be-

more expensive and less convenient to install and less dependable in. service. In',,ca-ses 'where' reduction of the friction in the bearing of the sealing element is of great importance, however, the ball thrust bearing 96 might be superior tothe flat ring thrust bearing 85.

While the sealing element of my invention preferably operates in planes disposed radially relative to the axis of rotation involved, the surfaces between which the sealing ring of my invention is compressed might comprise concentric cylindrical surfaces in which case the channel I8 would open at one end of the rubber ring I6, instead of centrally, and the bearing of my sealing element be a radial bearing. i

Fig. 5-. This element is compressed between 00- axial cylindrical surfaces IM and I02 of elements ofrotation between two members providing opposed adjacent surfaces and having rotational movement relative to each other about said'axis, said seal comprising: a non-yielding bearing disposed in said area and having opposite outside faces disposed in spaced relation with said surfaces; and a rubber. annulus having annular portions compressed between said faces and said surfaces and an annular impervious flexing portion connecting the annular portions aforesaid.

DANA E. KEIECH.

A sealing element I00 of this-type is shown in 

